Though imprisoned as a subversive by Chinese authorities, the intellectual who champions freedom of expression has remained unwaveringly optimistic.

Reporting from Beijing — Before he was anything else, a hunger striker or inmate, dissident or symbol, Liu Xiaobo was a bookish literature professor and an essayist desperate to be able to write about politics, art and life without restraint.

His dedication to writing has been his defining characteristic, those who know him say, and it's what hauled him into politics — an intense and dogged desire for the freedom of expression. Everything else, the years of struggle against the Communist Party and his unveiling as this year's Nobel Peace Prize laureate, flowed from that point.

For decades, Liu's clashes with Chinese authorities have come in waves, tangled up in the push and pull between an intellectual class keen for greater freedoms and a ruling party that has gone through various shifts in economic philosophy and political organization, ever determined to keep its grip on power.

Liu was born into a turbulent China in 1955, the child of intellectuals. He grew up in the industrial city of Changchun, a northeastern factory hub sometimes compared to Cincinnati. He moved to Beijing to study literature.

He started teaching, earned his PhD in comparative literature and appeared ready to settle into a quiet life. But Liu was soon pulled into the turbulent political life of a nation enthralled by new notions of democratic reform.

In 1989, the young professor rushed home from the United States, leaving a visiting-scholar post at Columbia University, to participate in the democracy movement that was sweeping China.

He was headed to Tiananmen Square, to plunge into events that shaped or squashed the political consciences of a generation, and which official China still cannot bring itself to address. The crushed demonstrations on the square, Liu later said, marked the "major turning point in my 50 years on life's road."

As national tensions simmered in the heart of the capital, Liu joined demonstrating students on the square in a hunger strike. And later, as tanks rumbled in, Liu convinced some of the students to flee the scene and save their lives.

He was branded a subversive and served his first stint in prison, 18 months. From then on, Liu would face obstacles to publishing or lecturing in his homeland. But he stayed in China, and he kept trying.

"Simply for expressing divergent political views and taking part in a peaceful and democratic movement, a teacher lost his podium, a writer lost the right to publish, and a public intellectual lost the chance to speak publicly," he wrote shortly before going to prison last year, where he remains today. "This was a sad thing, both for myself as an individual and, after three decades of reform and opening, for China."

After Liu's first prison term ended in 1991, the Communist Party continued to chafe at his writings. He was placed under house arrest in 1995, then ordered to a labor camp for "reeducation."

It was while in the camp that he married Liu Xia. The pair had met in college in the 1980s, drawn together by a shared love of poetry.

He was released in 1999, and for nearly a decade was disliked but tolerated by the government. But after he helped to pen a document known as Charter 08, a call for multiparty elections and democratic reform, Liu was arrested again.

Despite his travails, Liu has remained a man of deep optimism. He has stressed a belief that the world is moving inexorably toward more freedom and greater democracy.

This is what he told his friends, and what he told himself.

"One letter is enough / For me to transcend / And face you to speak," he wrote in a poem from prison.

His unwavering conviction that no authority could permanently block the natural human impulse to freedom struck an almost anachronistic tone, harking back to the crumbling of the Soviet bloc. (Charter 08 was modeled partly on Charter 77, the document that called for political change in communist Czechoslovakia.)

Even as his freedoms dwindled, Liu remained quietly, astoundingly upbeat. In a statement he penned last year, he insisted that the authorities who interrogated and prosecuted him were to be commended for their increasing professionalism.

He also noted that conditions in prison were improving, with music played for the inmates before meals.

"Getting to know the sincere, honest, responsible, good-hearted Liu really was a piece of good luck for me," he wrote of the guard who was in charge of his cell.

Some of his fellow dissidents disapproved, especially when Liu wrote last year that he had "no enemies, and no hatred." Although he rejected the actions of the state, he said, he still respected the "professions and personalities" of the individuals who spied, arrested, prosecuted and sentenced.